- otherwise there is actually no means of placing a site-site
  prefs.sh in the $WM_PROJECT_SITE/ directory

- leave bashrc/cshrc and prefs.{csh,sh} in etc/ for visibility

- use standard *.sh, *.csh endings

- need to trap possibly weird input within etc/bashrc, etc/cshrc and
  can't easily redirect stderr in csh.

- renamed clearEnv -> unset

- avoid editing of settings.{sh,csh}

- alternative to WM_PROJECT_INST_DIR/site for systems with locked down
  installation paths (eg, when packaged as RPM or deb)

  When "$WM_PROJECT_SITE" is defined, it is used in favour of
  "$WM_PROJECT_INST_DIR/site"

- can be reused for other (vector, tensor, ...) field types

- prevented the reloading from working properly (thanks Mattijs!)

- useful for debugging purposes